A hydrostatic-mechanical tractor transmission with an infinitely variable hydrostatic drive is already known from DE 10 2006 025 348 A1. The hydrostatic drive has a hydrostatic pump driven by an internal combustion engine and a hydraulic motor driven by the pump. The pump and the hydraulic motor are forcibly coupled by way of a single, common pivotable part and can be adjusted in such a manner that the pump can be pivoted between a minimum angle and a maximum angle, while the motor simultaneously pivots synchronously between a maximum pivot angle and a minimum angle. The pump is designed for a single pumping direction of the volume flow. A mechanical range-change transmission having several gear steps, that can be shifted via a clutch, is connected downstream.
A transmission device that has power spitting ability is additionally known from DE 19 52 966 A, comprising a variator, a double planetary gear set and a manual gearbox for implementing several operating ranges. The pump device and the motor device of the variator designed as a hydrostatic unit can be adjusted by way of a common yoke.